re PR c++/81197 (ICE with structured binding and lifetime-extended temporaries)

	PR c++/81197
	* cp-tree.h (cp_maybe_mangle_decomp): Declare.
	* decl.c (cp_maybe_mangle_decomp): New function.
	(cp_finish_decomp): Don't SET_DECL_ASSEMBLER_NAME here.
	* parser.c (cp_convert_range_for,
	cp_parser_decomposition_declaration): Call cp_maybe_mangle_decomp.
	* pt.c (tsubst_expr): Likewise.
	* mangle.c (find_decomp_unqualified_name): New function.
	(write_unqualified_name): Handle DECL_DECOMPOSITION_P
	where DECL_ASSEMBLER_NAME is already set.

	* g++.dg/cpp1z/decomp34.C: New test.

From-SVN: r255705

1 files changed, 56 insertions, 1 deletions

diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 6d4e591..ffd2b4c 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -1247,6 +1247,51 @@ write_template_prefix (const tree node)
   add_substitution (substitution);
 }
 
+/* As the list of identifiers for the structured binding declaration
+   DECL is likely gone, try to recover the DC <source-name>+ E portion
+   from its mangled name.  Return pointer to the DC and set len to
+   the length up to and including the terminating E.  On failure
+   return NULL.  */
+
+static const char *
+find_decomp_unqualified_name (tree decl, size_t *len)
+{
+  const char *p = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
+  const char *end = p + IDENTIFIER_LENGTH (DECL_ASSEMBLER_NAME (decl));
+  bool nested = false;
+  if (strncmp (p, "_Z", 2))
+    return NULL;
+  p += 2;
+  if (!strncmp (p, "St", 2))
+    p += 2;
+  else if (*p == 'N')
+    {
+      nested = true;
+      ++p;
+      while (ISDIGIT (p[0]))
+	{
+	  char *e;
+	  long num = strtol (p, &e, 10);
+	  if (num >= 1 && num < end - e)
+	    p = e + num;
+	  else
+	    break;
+	}
+    }
+  if (strncmp (p, "DC", 2))
+    return NULL;
+  if (nested)
+    {
+      if (end[-1] != 'E')
+	return NULL;
+      --end;
+    }
+  if (end[-1] != 'E')
+    return NULL;
+  *len = end - p;
+  return p;
+}
+
 /* We don't need to handle thunks, vtables, or VTTs here.  Those are
    mangled through special entry points.
 
@@ -1291,7 +1336,17 @@ write_unqualified_name (tree decl)
     {
       found = true;
       gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
-      write_source_name (DECL_ASSEMBLER_NAME (decl));
+      const char *decomp_str = NULL;
+      size_t decomp_len = 0;
+      if (VAR_P (decl)
+	  && DECL_DECOMPOSITION_P (decl)
+	  && DECL_NAME (decl) == NULL_TREE
+	  && DECL_NAMESPACE_SCOPE_P (decl))
+	decomp_str = find_decomp_unqualified_name (decl, &decomp_len);
+      if (decomp_str)
+	write_chars (decomp_str, decomp_len);
+      else
+	write_source_name (DECL_ASSEMBLER_NAME (decl));
     }
   else if (DECL_DECLARES_FUNCTION_P (decl))
     {